Wed, Aug 04, 2021:On Demand
Background/Question/Methods
Common gardens have been used in ecology and evolutionary biology for nearly a century. Reciprocal gardens, in which plant ecotypes are cross-transplanted among sites, have been used to investigate local adaptation and gene x environment interactions. We surveyed the literature to assess the characteristics of studies employing common gardens in order to identify gaps in our knowledge of focal species and life forms, variables measured, number of source and transplant sites, and range of manipulations made to make recommendations for the next generation of common garden studies. To carry out this survey, a randomly chosen set of articles was obtained using a search on ISI Web of Knowledge and “advanced” search for ‘COMMON GARDEN*’ OR ‘RECIPROCAL TRANSPLANT*’ OR ‘PROVENANCE’), then selected articles published from 1990 to 2020. The article information was sorted randomly, then articles were assessed in order by which they were sorted. Next, we scanned each title and abstract to assess whether an article was potentially relevant; if needed, we consulted the original article. In all, we surveyed relevancy of 408 of 7,668 articles before being able to assess a sufficient number to ensure statistical stability in the results.
Results/Conclusions For each article, we recorded the number of focal species, sources and planting sites; plant life form; continent and biome; whether plants were grown alone or in a community; measurements (e.g., morphology, physiology, genetic analyses); abiotic and biotic manipulations; and duration study. Of the 408 studies, we identified 111 papers that were relevant, and subsequently coded. The modal study was a single tree species growing in a monoculture sourced from two sites and growing at one site in a temperate forest in North America, with measurements on morphology and growth/physiology. Only a few studies conducted manipulations beyond transfer of plants, but the most common manipulation involved changes in water availability. Reciprocal garden studies should expand the range of growth forms investigated beyond provenance trials of timber trees, to ecological studies of foundational non-model species, as well as increase source and planting sites. We encourage studies to better incorporate biotic effects such as competition, herbivory, and the soil microbiome into experimental design to capture ecological reality. Moving forward, common gardens of ecological non-model species, combined with genomic analyses and incorporation of biotic factors, have the potential to further revolutionize our understanding adaptation.
Results/Conclusions For each article, we recorded the number of focal species, sources and planting sites; plant life form; continent and biome; whether plants were grown alone or in a community; measurements (e.g., morphology, physiology, genetic analyses); abiotic and biotic manipulations; and duration study. Of the 408 studies, we identified 111 papers that were relevant, and subsequently coded. The modal study was a single tree species growing in a monoculture sourced from two sites and growing at one site in a temperate forest in North America, with measurements on morphology and growth/physiology. Only a few studies conducted manipulations beyond transfer of plants, but the most common manipulation involved changes in water availability. Reciprocal garden studies should expand the range of growth forms investigated beyond provenance trials of timber trees, to ecological studies of foundational non-model species, as well as increase source and planting sites. We encourage studies to better incorporate biotic effects such as competition, herbivory, and the soil microbiome into experimental design to capture ecological reality. Moving forward, common gardens of ecological non-model species, combined with genomic analyses and incorporation of biotic factors, have the potential to further revolutionize our understanding adaptation.